Dental filling material.



A. G. MEIER.

DENTAL FILLING MATERIAL.

APPLICATION FILED JUNE 12. 1911.

1,008,845. Patented Nov. 14, 1911.

56 characteristics of a gold fillin tional ones, and which will ADOILPHUS G. MEIER, OF ST. LOUIS, MISSOURI.

DENTAL rrntme MATERIAL.

' Specification of Letters Patent.

Application filed June 12, 1911. Serial No. 632,803.

Patented Nov. 14, 1911.

To all whom 'it 'nw/y concern:

Be it known that I, ADOLPHUB G. MEIER, a citizen of the United States, and residing at St. Louis, State of Missouri, have invented certain new and useful Improvements in Dental Filling Materials, of which the following is a specification. This invention relates to dental filling materials and more particularly to dental foils.

Dental filling materials are usually furnished to dentists in the form of foils, and in use pieces of foil are folded and-plugged into the tooth cavity. One of the chief requirements of such a filling material is cohesiveness,for the pieces must when plugged into place cohere to form a solid and compact mass. The material most generally used is gold, since it possesses great cohesive properties. Due to'the fact however that the gold must have a high purity in order to possess this desirable property, the filling is necessarily expensive. One of the disadvantages of a gold filling is its high zhermal conductivity which causes discomort.

Various attempts have been made to sub- I stitute for gold a cheaper material but without success, since few materials possess the desirable cohesive property and at the same time are suitable for a tooth filling. Among others tin has been tried, and since tin is not cohesive to any great-extent it has been attempted to use it in combination with old 85 by placing a foil of tin between two oils of pure gold, cutting the layers into pieces and plugging the same into the tooth. Due to the fact however that tin lacks the necessary cohesive plro erty it requires from five to SIX times t e ength of time to plug a tooth in order to obtam a coherent and compact filling that is required with gold. This material is therefore impractical on account of the len th of time required for performing the ing 0 eration, making the cost of the work not 0 y excessive but also causing added discomfort to the patient. While therefore a filling material consisting of a. combination of tin and gold is cheaper than gold and producesa better filling, the total cost of the finished filling is higher.

The object of this invention is-therefore izpilproduce a dental fillin material which possess all the desirab e properties and and a'ddicohedve,

opegation to that required when pure gold is use In accordance with this invention a noncohesive metal is combined with a cohesive metal to produce a resultant roduct which will be cohesive. More speci cally stated a combination of a base metal such as tin, and gold is used in which the metals are so combined that the resultantproduct will possess all the desirable properties and characteristics that a tooth filling material should ave.

The drawing represents the novel foil forming the subject matter of this invention, Figure 1 being a view showing the different component parts of the foil and Fig. 2 being a section. T

The process of making this filling material Will be first described. Tin in 1ts pure state, cannot be electroplated with gold, therefore it is alloyed with another metal which will make it electro-platable. As an example, an alloy of tin and silver (90% Sn, 10% Ag) is made in a crucible under a hydrogen atmosphere so as to prevent oxidation of the tin. This alloy 1s then cast vin blocks about one inch wide and about one-fourth inch thick, and the blocks are then rolled and cut into pieces suitable for beating. These pieces are then annealed in a' h dro en atmos here and cleaned in a wee so ution of ydrochloric acid. The

pieces are then beat out in the form of a foil between gold beaters skins to nearl the hed product, or so as to require stll another beating. 'The foil is then electroplated with pure gold so that the finished product will contain about 25% gold In this electroplating operation the ordinary gold platingpractice is followed, using the usual cyamd solution. The plated 011 is then lgli-zen'a final beating between gold beaters s s to produce a more even surface and to properly unite the particles of electrolated gold with the -tm. This gives the hed product. The finished product repared as above Wlll contain about 25% gol ,67.5% tin, and 7.5% silver. The surfaces of the foil Wlll be pure gold, while the bod will be an alloy of tin and silver.. These di erent components of the roduct will be thoroughlyunited so as to mm a coherent structure. ,Since the coator surface is of ure 1d, the resultant foil will possess the esira 1e cohesive propthereby reducing thetime of the filling erty ofpur'e gold foil, and can therefore be, plugged to make a compact and coherent filling with practically the same amount of labor as is required when pure gold is used.

The gold and tin combination is'not in this and possesses more desirable properties and characteristics. The thermal conductivity of tin is very much lower than that of gold, and therefore the resultant product will have a lower conductivity, thus causing less discomfort due 'to this fact. Tin and therefore this product is more tolerant to the tooth structure itself than gold. A mixture of oxid, changing the entire mass of gold and ture. In making this change the filling expands slightly, driving it into and filling the smaller pores and cavities in the tooth.

In the specification certain proportions vhave been described and the steps of the process enumerated in a defined manner. It

, alloying metal.

will be understood however that these roportions and the series of steps have een used rather as illustrative, since various pro- Other metals than silver may be alloyed with tin to make it platable, for instance copper may be substituted for silver. Silver is however found to be more desirable. It will be understoodtherefore that this invention is not to be limited to the use of any specific Having thus described the invention what is claimed is:

1. A composite dental foil comprising a body containing tin, and a plating of gold. 2. A composite dental foil comprising a tin alloy plated with gold. gold and tin in a tooth forms a peculiar :tin-silver alloy plated with old. tin'into a structure resembling a tooth struc- 3. A composite dental foil comprising a In testimony whereof I a x my signature in presence of two witnesses.

ADOLPHUS o. MEIER. 

